Dental assistants perform a variety of duties in the dental office, including helping the dentist examine and treat patients and completing laboratory and office work. They assist the dentist by preparing patients for dental exams, handing the dentist the proper instruments, taking and processing X-rays, preparing materials for making impressions and restorations, and instructing patients in oral health care. They also perform administrative and clerical tasks so that the office runs smoothly and the dentist's time is available for working with patients. There are more than 309,540 dental assistants employed in the United States.